Program for addition of two matrices

Given two N x M matrices. Find a N x M matrix as the sum of given matrices each value at the sum of values of corresponding elements of the given two matrices. 

Approach: Below is the idea to solve the problem.

Iterate over every cell of matrix (i, j), add the corresponding values of the two matrices and store in a single matrix i.e. the resultant matrix.

Follow the below steps to Implement the idea:

• Initialize a resultant matrix res[N][M].
• Run a for loop for counter i as each row and in each iteration:
  • Run a for loop for counter j as each column and in each iteration:
    • Add values of the two matrices for index i, j and store in res[i][j].
• Return res.

Below is the Implementation of above approach.

C++

// C++ program for addition
// of two matrices
#include <bits/stdc++.h>
using namespace std;
#define N 4

// This function adds A[][] and B[][], and stores
// the result in C[][]
void add(int A[][N], int B[][N], int C[][N])
{
    int i, j;
    for (i = 0; i < N; i++)
        for (j = 0; j < N; j++)
            C[i][j] = A[i][j] + B[i][j];
}

// Driver code
int main()
{
    int A[N][N] = { { 1, 1, 1, 1 },
                    { 2, 2, 2, 2 },
                    { 3, 3, 3, 3 },
                    { 4, 4, 4, 4 } };

    int B[N][N] = { { 1, 1, 1, 1 },
                    { 2, 2, 2, 2 },
                    { 3, 3, 3, 3 },
                    { 4, 4, 4, 4 } };

    int C[N][N]; // To store result
    int i, j;

    // Function Call
    add(A, B, C);

    cout << "Result matrix is " << endl;
    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++)
            cout << C[i][j] << " ";
        cout << endl;
    }

    return 0;
}

// This code is contributed by rathbhupendra

C

// C Program to add two matrix
#include <stdio.h>
#define N 4

// This function adds A[][] and B[][], and stores
// the result in C[][]
void add(int A[][N], int B[][N], int C[][N])
{
    int i, j;
    for (i = 0; i < N; i++)
        for (j = 0; j < N; j++)
            C[i][j] = A[i][j] + B[i][j];
}

int main()
{
    int A[N][N] = { { 1, 1, 1, 1 },
                    { 2, 2, 2, 2 },
                    { 3, 3, 3, 3 },
                    { 4, 4, 4, 4 } };

    int B[N][N] = { { 1, 1, 1, 1 },
                    { 2, 2, 2, 2 },
                    { 3, 3, 3, 3 },
                    { 4, 4, 4, 4 } };

    int C[N][N]; // To store result
    int i, j;
    add(A, B, C);

    printf("Result matrix is \n");
    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++)
            printf("%d ", C[i][j]);
        printf("\n");
    }

    return 0;
}

Java

// Java program for addition
// of two matrices

class GFG {
    static final int N = 4;

    // This function adds A[][] and B[][], and stores
    // the result in C[][]
    static void add(int A[][], int B[][], int C[][])
    {
        int i, j;
        for (i = 0; i < N; i++)
            for (j = 0; j < N; j++)
                C[i][j] = A[i][j] + B[i][j];
    }

    // Driver code
    public static void main(String[] args)
    {
        int A[][] = { { 1, 1, 1, 1 },
                      { 2, 2, 2, 2 },
                      { 3, 3, 3, 3 },
                      { 4, 4, 4, 4 } };

        int B[][] = { { 1, 1, 1, 1 },
                      { 2, 2, 2, 2 },
                      { 3, 3, 3, 3 },
                      { 4, 4, 4, 4 } };

        // To store result
        int C[][] = new int[N][N];
        int i, j;
        add(A, B, C);

        System.out.print("Result matrix is \n");
        for (i = 0; i < N; i++) {
            for (j = 0; j < N; j++)
                System.out.print(C[i][j] + " ");
            System.out.print("\n");
        }
    }
}

// This code is contributed by Anant Agarwal.

Python3

# Python3 program for addition
# of two matrices

N = 4

# This function adds A[][]
# and B[][], and stores
# the result in C[][]


def add(A, B, C):

    for i in range(N):
        for j in range(N):
            C[i][j] = A[i][j] + B[i][j]


# driver code
A = [[1, 1, 1, 1],
     [2, 2, 2, 2],
     [3, 3, 3, 3],
     [4, 4, 4, 4]]

B = [[1, 1, 1, 1],
     [2, 2, 2, 2],
     [3, 3, 3, 3],
     [4, 4, 4, 4]]

C = A[:][:]  # To store result

add(A, B, C)

print("Result matrix is")
for i in range(N):
    for j in range(N):
        print(C[i][j], " ", end='')
    print()

# This code is contributed
# by Anant Agarwal.

C#

// C# program for addition
// of two matrices
using System;

class GFG {
    static int N = 4;

    // This function adds A[][] and B[][], and stores
    // the result in C[][]
    static void add(int[, ] A, int[, ] B, int[, ] C)
    {
        int i, j;
        for (i = 0; i < N; i++)
            for (j = 0; j < N; j++)
                C[i, j] = A[i, j] + B[i, j];
    }

    // Driver code
    public static void Main()
    {
        int[, ] A = { { 1, 1, 1, 1 },
                      { 2, 2, 2, 2 },
                      { 3, 3, 3, 3 },
                      { 4, 4, 4, 4 } };

        int[, ] B = { { 1, 1, 1, 1 },
                      { 2, 2, 2, 2 },
                      { 3, 3, 3, 3 },
                      { 4, 4, 4, 4 } };

        // To store result
        int[, ] C = new int[N, N];
        int i, j;
        add(A, B, C);

        Console.WriteLine("Result matrix is ");
        for (i = 0; i < N; i++) {
            for (j = 0; j < N; j++)
                Console.Write(C[i, j] + " ");
            Console.WriteLine();
        }
    }
}

// This code is contributed by vt_m.

PHP

<?php
// This function adds A[][] and
// B[][], and stores the result in C[][]
function add(&$A, &$B, &$C)
{
    $N = 4;
    for ($i = 0; $i < $N; $i++)
        for ($j = 0; $j < $N; $j++)
            $C[$i][$j] = $A[$i][$j] +
                         $B[$i][$j];
}

// Driver code
$A = array(array(1, 1, 1, 1),
           array(2, 2, 2, 2),
           array(3, 3, 3, 3),
           array(4, 4, 4, 4));

$B = array(array(1, 1, 1, 1),
           array(2, 2, 2, 2),
           array(3, 3, 3, 3),
           array(4, 4, 4, 4));

$N = 4;
add($A, $B, $C);

echo "Result matrix is \n";
for ($i = 0; $i < $N; $i++)
{
    for ($j = 0; $j < $N; $j++)
    {
        echo $C[$i][$j];
        echo " ";
    }
    echo "\n" ;
}

// This code is contributed
// by Shivi_Aggarwal
?>

Javascript

<script>

// Javascript program for addition
// of two matrices

let N = 4;

// This function adds A[][] and B[][], and stores
// the result in C[][]
function add(A, B, C)
{
    let i, j;
    for (i = 0; i < N; i++)
        for (j = 0; j < N; j++)
            C[i][j] = A[i][j] + B[i][j];
}

// Driver code
    let A = [ [1, 1, 1, 1],
                    [2, 2, 2, 2],
                    [3, 3, 3, 3],
                    [4, 4, 4, 4]];

    let B = [ [1, 1, 1, 1],
                    [2, 2, 2, 2],
                    [3, 3, 3, 3],
                    [4, 4, 4, 4]];

    // To store result
    let C = new Array(N);
    for (let k = 0; k < N; k++)
        C[k] = new Array(N);

    let i, j;
    add(A, B, C);

    document.write("Result matrix is <br>");
    for (i = 0; i < N; i++)
    {
        for (j = 0; j < N; j++)
            document.write(C[i][j] + " ");
        document.write("<br>");
    }

</script>

Output

Result matrix is 
2 2 2 2 
4 4 4 4 
6 6 6 6 
8 8 8 8 

Time complexity: O(n²). 
Auxiliary space: O(n²).  since n² extra space has been taken for storing results

The program can be extended for rectangular matrices. The following post can be useful for extending this program. 

How to pass a 2D array as a parameter in C?